Evaporative Subcooling

ABSTRACT

A refrigeration system comprises an indoor exchanger, an outdoor exchanger, a fluid collector configured to collect condensate from the indoor exchanger, and a fluid distributor configured to pass the condensate from the fluid collector over at least a portion of the outdoor exchanger. The outdoor exchanger comprises a main coil, and the subcooling coil. The indoor exchanger and the outdoor exchanger are operable in at least a cooling mode where the indoor coil is configured to absorb heat in the cooling mode and the outdoor coil is configured to release heat in the cooling mode. The fluid distributor may be configured to pass the condensate over at least a portion of the subcooling coil.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 119(e) to U.S.Provisional Patent Application No. 61/926,720 filed on Jan. 13, 2014 byStephen Stewart Hancock and entitled “Evaporative Subcooling,” and U.S.Provisional Patent Application No. 62/010,266 filed on Jun. 10, 2014 byStephen Stewart Hancock and entitled “Evaporative Subcooling,” thedisclosures of which are hereby incorporated by reference in theirentirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

Heating, ventilation, and air conditioning systems (HVAC systems)generally comprise one or more heat exchangers generally referred to as“condensers” that may be comprise a condenser coil, and may beassociated with one or more compressors and a fan assembly. Inoperation, a compressor may compress refrigerant and dischargesuperheated refrigerant (i.e., refrigerant at a temperature greater thana saturation temperature of the refrigerant) to the condenser coil. Asthe refrigerant passes through the condenser coil, a fan assembly may beconfigured to selectively force air into contact with the condensercoil. In response to the air contacting the condenser coil, heat may betransferred from the refrigerant to the air, thereby desuperheating therefrigerant and/or otherwise reducing a temperature of the refrigerant.In some cases, the temperature of the refrigerant within the condensercoil is reduced to a saturation temperature of the refrigerant.

Continued removal of heat from the refrigerant at the saturationtemperature in combination with appropriately maintained pressure withinthe condenser coil may result in transforming at least some orsubstantially all of the gaseous phase refrigerant to liquid phaserefrigerant. Refrigerant may generally exit the condenser coil in aliquid phase and/or a gaseous and liquid mixed phase. The refrigerantmay thereafter be delivered from the condenser coil to a refrigerantexpansion device where the refrigerant pressure is reduced and afterwhich, the refrigerant is selectively discharged into a so-calledevaporator coil of the HVAC system that may provide a cooling function.

SUMMARY

In an embodiment, a refrigeration system comprises an indoor exchanger,an outdoor exchanger, a fluid collector configured to collect condensatefrom the indoor exchanger, and a fluid distributor configured to passthe condensate from the fluid collector over at least a portion of theoutdoor exchanger. The outdoor exchanger comprises a main coil, and thesubcooling coil. The indoor exchanger and the outdoor exchanger areoperable in at least a cooling mode where the indoor coil is configuredto absorb heat in the cooling mode and the outdoor coil is configured torelease heat in the cooling mode. The refrigeration system may alsoinclude a pump configured to receive the condensate and pass thecondensate to the fluid distributor. The fluid distributor may beconfigured to pass the condensate over at least a portion of thesubcooling coil. The indoor exchanger and the outdoor exchanger may beoperable in a heating mode where the indoor coil is configured torelease heat in the heating mode and the outdoor coil is configured toabsorb heat in the heating mode. The fluid distributor may comprise adrip system or a spray nozzle. The fluid distributor may be configuredto pass the condensate over at least the portion of the outdoorexchanger in a liquid state. The refrigeration system may also include acondensate storage vessel in fluid communication with the fluidcollector and the fluid distributor.

In an embodiment, a cooling system comprises an evaporator exchanger, acondenser exchanger, a fluid collector configured to collect condensatefrom the evaporator exchanger, a fluid conduit in fluid communicationwith the fluid collector, and a fluid distributor in fluid communicationwith the fluid conduit. The fluid distributor is configured to pass thecondensate over at least a portion of the condenser exchanger. Thecondenser exchanger comprises a main coil, and a subcooling coil, wherethe condenser coil is configured to subcool at least a portion of therefrigerant in the subcooling coil. The evaporator coil is configured toabsorb heat to evaporate at least a portion of a refrigerant, and thecondenser coil is configured to release heat and condense at least aportion of the refrigerant in the main coil. The cooling system may alsoinclude a pump in fluid communication with the fluid conduit, and thepump may be configured to pass the fluid to the fluid distributor. Thefluid distributor may comprise a drip system disposed above thecondenser exchanger. The fluid distributor may be configured to pass thecondensate over at least a portion of the subcooling coil. Thesubcooling coil may be disposed above the main coil. The cooling systemmay also include a compressor disposed in a first fluid line between anoutlet of the evaporator exchanger and an inlet of the condenserexchanger, and an expansion device disposed in a second fluid linebetween an outlet of the condenser exchanger and an inlet of theevaporator exchanger. The compressor may be configured to draw arefrigerant from the outlet of the evaporator exchanger, compress therefrigerant, and pass the refrigerant to inlet of the condenserexchanger. The expansion device may be configured to receive arefrigerant from the outlet of the condenser exchanger, expand therefrigerant, and pass the refrigerant to inlet of the evaporatorexchanger. The cooling system may also include a blower that may beconfigured to cause air to pass over the condenser exchanger when thecondensate is passed over at least the portion of the condenserexchanger. The cooling system may also include a condensate storagevessel in fluid communication with the fluid collector and the fluiddistributor. The cooling system may also include a controller that isconfigured to cause the condensate storage vessel to collect condensatefrom the fluid collector, detect a condition associated with the coolingsystem, and transfer the condensate from the condensate storage vesselto the fluid distributor when the condition exceeds a threshold.

In an embodiment, a method of cooling a refrigerant comprisesevaporating a refrigerant in an indoor exchanger, condensing water onthe indoor exchanger during the evaporating, collecting the watercondensed on the indoor exchanger, distributing the water over at leasta portion of an outdoor exchanger, evaporating the water, and coolingthe refrigerant in the outdoor exchanger in response to the evaporating.Evaporating the water may comprise evaporating the water when the wateris in contact with the outdoor exchanger. Distributing the water over atleast the portion of the outdoor exchanger may comprise distributing thewater over a subcooling coil of the outdoor exchanger. Cooling therefrigerant may comprise subcooling the refrigerant in the subcoolingcoil in response to evaporating the water. The refrigerant may besubcooled at least about 5° F. to about 30° F. The method may alsoinclude pumping the water from the indoor exchanger to the outdoorexchanger and/or completely condensing the refrigerant leaving theoutdoor exchanger in response to cooling the refrigerant. Collecting thewater may comprise storing the water condensed on the indoor exchangerin a condensate storage vessel. Distributing the water over at least aportion of the outdoor exchanger may comprise passing the water from thecondensate storage vessel to the outdoor exchanger, which may or may notoccur in response to a controller determining that the method isoccurring at a peak demand period. The method may also include measuringa condition associated with at least one of the indoor exchanger, theoutdoor exchanger, an indoor location, or an outdoor location, comparingthe condition with one or more thresholds, and releasing the water fromthe condensate storage vessel when the condition exceeds at least onethreshold.

These and other features will be more clearly understood from thefollowing detailed description taken in conjunction with theaccompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and theadvantages thereof, reference is now made to the following briefdescription, taken in connection with the accompanying drawings anddetailed description:

FIG. 1 is a simplified schematic diagram of an HVAC system according toan embodiment of the disclosure.

FIG. 2 is a simplified schematic diagram of an outdoor heat exchangeraccording to an embodiment of the disclosure.

FIG. 3 is another simplified schematic diagram of an HVAC systemaccording to an embodiment of the disclosure.

FIG. 4 is a simplified schematic diagram of another HVAC systemaccording to an embodiment of the disclosure.

FIG. 5 is a simplified schematic diagram of a computer system accordingto an embodiment of the disclosure.

DETAILED DESCRIPTION

In the drawings and description that follow, like parts are typicallymarked throughout the specification and drawings with the same referencenumerals, respectively. In addition, similar reference numerals mayrefer to similar components in different embodiments disclosed herein.The drawing figures are not necessarily to scale. Certain features ofthe invention may be shown exaggerated in scale or in somewhat schematicform and some details of conventional elements may not be shown in theinterest of clarity and conciseness. The present invention issusceptible to embodiments of different forms. Specific embodiments aredescribed in detail and are shown in the drawings, with theunderstanding that the present disclosure is not intended to limit theinvention to the embodiments illustrated and described herein. It is tobe fully recognized that the different teachings of the embodimentsdiscussed herein may be employed separately or in any suitablecombination to produce desired results.

HVAC systems are being improved in order to provide increased efficiencyand cooling capacity. Disclosed herein is an HVAC system that utilizescondensation formed on an indoor heat exchanger to cool, and in someinstances subcool, the refrigerant passing through the outdoor heatexchanger. As used herein, the condensation formed on the indoor heatexchanger may be referred to as “condensate.” During a normal coolingmode, the indoor heat exchanger responsible for cooling the indoor aircan utilize 20% to 25% of the cooling capacity in condensing themoisture in the indoor air. This condensation process occurs at a nearconstant temperature and does not significantly contribute to thelowering the dry-bulb temperature of the indoor air. This condensate istypically discarded to a waste water source, and the energy required tocondense the water is essentially lost.

Rather than discard the condensate formed on the indoor heat exchanger,the present disclosure teaches transferring the water to a fluiddistributor and using the fluid distributor to distribute the water overat least a portion of the outside heat exchanger. The condensate can bedistributed over the outside heat exchanger as it is generated on theindoor heat exchanger, or in some embodiments, the condensate can bestored and used during high demand periods (e.g., peak demandconditions). In some embodiments, the condensate can be distributed overa subcooling portion of the outdoor heat exchanger in order to subcoolthe refrigerant prior to cycling the refrigerant back into the indoorheat exchanger. Applying the condensate to the subcooling portion mayreduce or avoid the condensate inducing circuit imbalance whileincreasing the condenser capacity up to 20% to 30%. The use of thecondensate may also enable depression of the condensing temperature morethan using outdoor air alone. Further, the use of the condensate formedon the indoor heat exchanger may provide for a relatively pure watersource that should be free of dissolved minerals and other chemicalsthat could foul the outdoor heat exchanger. The recycling of the wateralso reclaims a portion of the energy that was lost during thecondensation process, reduces the need to discard the water, andprovides the water at the time that it is needed (e.g., during thecooling cycle).

Referring now to FIG. 1, a simplified schematic diagram of an HVACsystem 100 is shown according to an embodiment of the disclosure. HVACsystem 100 generally comprises an indoor unit 102, an outdoor unit 104,and a system controller 106. The system controller 106 may generallycontrol operation of the indoor unit 102 and/or the outdoor unit 104.

The HVAC system 100 illustrated in FIG. 1 may be referred to as a splitsystem in some contexts, where the split system 100 comprises an indoorunit 102 located separately from the outdoor unit 104. While a splitsystem is described herein, the systems and methods described herein maybe equally applicable to other HVAC systems as well. In some embodimentsof an HVAC system 100, the system 100 may comprise a package system inwhich one or more of the components of the indoor unit 102 and one ormore of the components of the outdoor unit 104 are carried together in acommon housing or package. In still other embodiments, the HVAC system100 may comprise a ducted system where the indoor unit 102 is remotelylocated from the conditioned zones, thereby requiring air ducts to routethe circulating air.

Indoor unit 102 generally comprises an indoor heat exchanger 108, anindoor fan 110, an expansion device 112, and a fluid collection assembly109. The indoor heat exchanger 108 is configured to allow heat exchangebetween a refrigerant carried within internal tubing of the indoor heatexchanger 108 and fluids that contact the indoor heat exchanger 108 butthat are kept segregated from the refrigerant. In a cooling mode, therefrigerant received within the indoor heat exchanger 108 can be coolerthan the fluid passing over the exterior of the indoor heat exchanger108. The resulting heat absorption by the refrigerant within the indoorheat exchanger may result in the vaporization of the refrigerant withinthe indoor heat exchanger 108. For this reason, the indoor heatexchanger may be referred to as an evaporator or evaporator exchanger insome contexts. Various types of exchangers can be used as the indoorheat exchanger 108 including, but not limited to, a plate fin heatexchanger, a spine fin heat exchanger, a microchannel heat exchanger, orany other suitable type of heat exchanger.

The indoor fan 110 serves to create the flow of the fluid that contactsthe indoor heat exchanger 108. In general, the indoor fan 110 drives anair flow over the exterior of the indoor heat exchanger 108 tubes aswell as driving the ventilation system to circulate the air within theindoor environment. While described as a fan, various types of fans andblowers can be used as the indoor fan 110. In an embodiment, the indoorfan 110 may be a centrifugal blower comprising a blower housing, ablower impeller at least partially disposed within the blower housing,and a blower motor configured to selectively rotate the blower impeller.In other embodiments, the indoor fan 110 may comprise a mixed-flow fanand/or any other suitable type of fan. The indoor fan 110 may beconfigured as a modulating and/or variable speed fan capable of beingoperated at many speeds over one or more ranges of speeds. In otherembodiments, the indoor fan 110 may be configured as a multiple speedfan capable of being operated at a plurality of operating speeds byselectively electrically powering different ones of multipleelectromagnetic windings of a motor of the indoor fan 110. In yet otherembodiments, the indoor fan 110 may be a single speed fan.

The expansion device 112 is configured to receive a relativelyhigh-pressure refrigerant from the outdoor heat exchanger 114 and reducethe pressure of the refrigerant (e.g., expanding the refrigerant) asmeasured across the expansion device 112 prior to the refrigerantentering the indoor heat exchanger 108. In this embodiment, theexpansion device 112 is disposed between and is in fluid communicationwith the outlet of the outdoor heat exchanger114 and the inlet of theindoor heat exchanger 108. In some embodiments, the expansion device 112may also control an amount of refrigerant passing through the expansiondevice 112. The pressure reduction results in a cooling of therefrigerant, which is then used to absorb heat into the refrigerant inthe indoor heat exchanger 108 while correspondingly cooling the fluid(e.g., the indoor air) passing over the indoor heat exchanger 108.

The expansion device 112 may include various forms. In an embodiment,the expansion device 112 may comprise an electronically controlled motordriven electronic expansion valve (EEV). In some embodiments, theexpansion device 112 may comprise a thermostatic expansion valve, anisenthalpic expansion valve, a capillary tube assembly, an orificeand/or any other suitable expansion device or metering device. Theexpansion device 112 may comprise and/or be associated with arefrigerant check valve and/or refrigerant bypass.

The fluid collection assembly 109 is configured to receive at least somecondensate formed on the indoor heat exchanger 108 during operation ofthe indoor heat exchanger 108. In general, the cool refrigerant locatedwithin the indoor heat exchanger 108 when the system 100 is operating ina cooling mode may result in the condensation of at least a portion ofany moisture in the fluid passing over the of the indoor heat exchanger108. The fluid collection assembly 109 may be located in a suitableposition to collect and receive the condensate formed on the indoor heatexchanger 108. In an embodiment, the fluid collection assembly 109 maycomprise a drain pan having a substantially open box-shaped structure.In this embodiment, the fluid collection assembly 109 may comprise fourgenerally rectangular side walls and a generally rectangular bottomwall. While described as being rectangular, any suitable shape orconfiguration can be used so long as at least a portion of thecondensate is collected from the indoor heat exchanger 108.

The condensate may be used with the outdoor heat exchanger 114 asdescribed herein. In order to allow the condensate to be transferred tothe outdoor heat exchanger 114, the fluid collection assembly 109 maycomprise a port 105 or other opening at or near the bottom of the fluidcollection assembly 109 to allow at least a portion of the collectedcondensate to leave the fluid collection assembly 109. In someembodiments, the fluid may flow by gravity flow to a fluid distributor111 associated with the outdoor heat exchanger 114, as described in moredetail herein.

In some embodiments, an optional pump 107 may be disposed between and influid communication with the port 105 and the fluid distributor 111. Thepump 107 may generally be configured to provide the driving force tocause the condensate to flow from the fluid collection assembly 109 tothe fluid distributor 111. Any suitably sized pump 107 may be used totransfer the condensate from the fluid collection assembly 109 to thefluid distributor 111. Various factors may be considered when selectingthe type and capacity (e.g., the volumetric capacity, pumping head,etc.) of the pump 107 such as the relative locations of the fluidcollection assembly 109, the fluid losses associated with the fluidconduits between the pump 107 and the fluid distributor 111, thepressure losses associated with the fluid distributor 111, the amount ofcondensate generated on the indoor heat exchanger 108, and the like. Inan embodiment, the pump may comprise a positive displacement pump, acentrifugal pump, or any other suitable pump, and the pump 107 mayoperate continuously, intermittently, and/or selectively, for example,when a condensate level is detected in the fluid collection assembly 109(using, for example, a fluid level detector).

The outdoor unit 104 generally comprises an outdoor heat exchanger 114,a compressor 116, an outdoor fan 118, and a fluid distributor 111. Theoutdoor heat exchanger 114 is configured to allow heat exchange betweena refrigerant carried within internal tubing of the outdoor heatexchanger 114 and fluids (e.g., outdoor air) that contact the outdoorheat exchanger 114 but that are kept segregated from the refrigerant. Ina cooling mode, the refrigerant received within the outdoor heatexchanger 114 through inlet line 115 can be warmer than the fluidpassing over the exterior of the outdoor heat exchanger 114. Theresulting heat loss by the refrigerant within the outdoor heat exchanger114 may result in the partial or complete condensation of therefrigerant within the outdoor heat exchanger 114. For this reason, theoutdoor heat exchanger 114 may be referred to as a condenser orcondenser exchanger in some contexts. Various types of exchangers can beused as the outdoor heat exchanger 114 including, but not limited to, aplate fin heat exchanger, a spine fin heat exchanger, a microchannelheat exchanger, or any other suitable type of heat exchanger.

While the outdoor heat exchanger 114 is described as being outside oroutdoors, the outdoor heat exchanger 114 does not have to be installedphysically outdoors. For example, the outdoor heat exchanger 114 can beinstalled within a building while having ducting to contact exterior airwith the outdoor heat exchanger 114. In some embodiments, the heatexchange between the outdoor heat exchanger 114 and the exterior oroutdoor air can occur directly or indirectly via an intermediate heattransfer fluid.

The compressor 116 can be disposed between and in fluid communicationwith the outlet of the indoor heat exchanger 108 and the inlet of theoutdoor heat exchanger 114. The compressor 116 may be configured toreceive the refrigerant from the indoor heat exchanger 108 through line119, compress the refrigerant, and pass the refrigerant to the outdoorheat exchanger 114 through line 115. As the refrigerant is compressed,the pressure and temperature of the refrigerant may rise, thereby allowthe heat to be released from the refrigerant within the outdoor heatexchanger 114. Various types of compressors are known and may besuitable for use with the system 100. In an embodiment, the compressor116 may comprise a multiple speed scroll type compressor configured toselectively pump refrigerant at a plurality of mass flow rates. In someembodiments, the compressor 116 may comprise a modulating compressorcapable of operation over one or more speed ranges, a reciprocating typecompressor, a single speed compressor, and/or any other suitablerefrigerant compressor and/or refrigerant pump.

In an embodiment as schematically illustrated in FIG. 2, the outdoorheat exchanger 114 may comprise a condensing section 204 and asubcooling section 202. As used herein, subcooling refers to a reductionin the temperature of the refrigerant below its saturation temperature(e.g., its condensation temperature) at the pressure within the outdoorheat exchanger 114. The condensing section 204 may comprise a main coil205, and the subcooling section 202 may comprise a subcooling coil 203.The terms main coil and subcooling coil can refer to any type of heatexchanger and not meant to describe or be limited to any particulardesign. In an embodiment, the main coil 205 and the subcooling coil 203can be two separate heat exchangers, or in some embodiments, they can becombined in various ways, for example by sharing common heat transferfins 206. The heat transfer fins 206 may be constructed of metal or anyother thermally conductive material to allow for the transfer of heatfrom the tubes into the heat transfer fins and consequently to theexternal fluid flowing over the heat transfer fins 206.

In an embodiment, the main coil 205 may comprise a series of refrigerantconveying tubes traversing a plurality of heat transfer fins 206. Theoutside fluid (e.g., outdoor air) can be conveyed across the heattransfer fins 206 and/or the plurality of refrigerant conveying tubes.The main coil 205 may receive a refrigerant through the inlet line 115and pass the refrigerant to an inlet header 208 (e.g., a distributor)that is coupled to and in fluid communication with an outlet header 212(e.g., a collector) by a plurality of cross-flow tubes 210. Each of thecross-flow tubes 210 may be in thermal contact with one or more of theheat transfer fins 206. The refrigerant may generally flow through oneof the cross-flow tubes 210 from the inlet header 208 to the outletheader 212. As heat is removed from the refrigerant, the refrigerant maypartially or completely condense within the cross-flow tubes 210.

The subcooling coil 203 may also comprise one or more refrigerantconveying tubes 216 traversing a plurality of heat transfer fins 206across which the outside fluid (e.g., outdoor air) can be conveyed. Theheat transfer fins 206 may be coupled to both the subcooling coils 203and the main coils 205. The subcooling coil 203 may receive therefrigerant from the main coil 205 through an inlet line 214 in fluidcommunication with the outlet header 212. The refrigerant may generallyflow through the subcooling tubes 216 before passing out of thesubcooling coil 203 through outside heat exchanger outlet line 117. Therefrigerant may be received within the inlet line 214 in a completelyliquid phase or mixed gas/liquid phase. As the refrigerant passesthrough the subcooling tubes 216, the refrigerant may be completelycondensed and subcooled below the saturation temperature (e.g., thecondensation temperature).

For performance reasons, there may be more tubes in the main coils 205than in the subcooling coil 203. For example, the refrigerant passingthrough the main coils 205 may comprise a gaseous or mixed gas/liquidphase. Upon the condensation of the refrigerant, the reduced volume ofthe liquid phase refrigerant may be transported through fewer subcoolingtubes 216 in the subcooling coil 203.

The outdoor fan 118 serves to create the flow of the fluid that contactsthe outdoor heat exchanger 114. In general, the outdoor fan 118 drivesan air flow over the exterior of the outdoor heat exchanger 118 tubes.While described as a fan, various types of fans and blowers can be usedas the indoor fan 110. In an embodiment, the outdoor fan 118 may be anaxial fan comprising a fan blade assembly and fan motor configured toselectively rotate the fan blade assembly. In other embodiments, theoutdoor fan 118 may comprise a mixed-flow fan, a centrifugal blower,and/or any other suitable type of fan and/or blower. The outdoor fan 118is configured as a modulating and/or variable speed fan capable of beingoperated at many speeds over one or more ranges of speeds. In otherembodiments, the outdoor fan 118 may be configured as a multiple speedfan capable of being operated at a plurality of operating speeds byselectively electrically powering different ones of multipleelectromagnetic windings of a motor of the outdoor fan 118. In yet otherembodiments, the outdoor fan 118 may be a single speed fan.

The outdoor fan 118 may be configured to draw air through the outdoorheat exchanger 118 and/or blow air into the outdoor heat exchanger 118.While illustrated as being above the outdoor exchanger 114, the outdoorfan 118 may be disposed below, within, or adjacent the outdoor heatexchanger 114. In some embodiments, the outdoor fan 118 may beconfigured to create an air flow pattern over the outdoor heat exchanger114 such that the air passes over the subcooling section 202 prior topassing over the condensing section 204, thereby creating acounter-current flow pattern within the outdoor heat exchanger 114. Insome embodiments, a cross-current flow pattern may be established wherethe external fluid (e.g., the outdoor air) is drawn across thesubcooling section 202 and the condensing section 204. Any othersuitable flow patterns or configurations are also possible.

The fluid distributor 111 is configured to receive the condensate fromthe fluid collection assembly 109 and pass the condensate over at leasta portion of the outdoor heat exchanger 114. For example, the fluiddistributor 111 may be configured to pass the condensate over thecondensing section 204, the subcooling section 202, and/or any portionthereof. The fluid distributor 111 is coupled to and in fluidcommunication with the condensate line 113, which is in fluidcommunication with the fluid collection assembly 109 and the optionalpump 107. The fluid distributor 111 may comprise any device suitable forpassing the condensate over the outdoor heat exchanger 114. In anembodiment, the fluid distributor 111 may pass at least a portion of thecondensate over the subcooling section 202 of the outdoor heat exchanger114. In some embodiments, the fluid distributor 111 may pass at least aportion of the condensate over the condensing section 204 of the outdoorheat exchanger 114. The use of the condensate on the outdoor heatexchanger 114, and in some embodiments the subcooling section 202, mayresult in subcooling of the refrigerant to a temperature below acomparable outdoor heat exchanger not having the condensate contactingat the portion of the comparable outdoor heat exchanger. In someembodiments, the fluid distributor 111 may be configured to only receivea fluid (e.g., the condensate) condensing on the indoor heat exchanger108 and no other source.

In an embodiment, the fluid distributor 111 may comprise a drip system.In this embodiment, the fluid distributor may comprise tubing having oneor more openings, ports, orifices, or other permeable surface to allowthe condensate to flow from an interior of the tubing to an exterior ofthe tubing. For example, the fluid distributor may comprise a permeabletubing to allow the condensate to flow through the permeable tubing anddownward onto the outdoor heat exchanger 114. The fluid distributor 111may then be configured to allow the condensate to drip off of the fluiddistributor 111 and contact the outdoor heat exchanger 114. Since thedrip system may rely on gravity to carry the condensate into contactwith the outdoor heat exchanger, the fluid distributor 111 may bedisposed above or over the outdoor heat exchanger 114. Further, thefluid distributor may be configured to allow the condensate to contactthe outdoor heat exchanger 114 in a liquid state. The condensate maythen be allowed to evaporate from the outdoor heat exchanger 114,thereby absorbing and removing heat from the refrigerant passing throughthe outdoor heat exchanger 114.

When the fluid distributor 111 comprises a drip system, the fluiddistributor 111 may be configured to allow the condensate to contact thesubcooling section 202 prior to any condensate contacting the condensingsection 204. In an embodiment, the subcooling section 202 including thesubcooling coil 203 may be located above the condensing section 204including the condensing coil 205. This may allow the condensate to bedistributed from the top of the outdoor heat exchanger 114 so that thecondensate may first contact the subcooling coil 203, and any excesscondensate not vaporized while in contact with the subcooling coil 203may then flow into contact with the condensing coil 205. This may allowthe condensate to be used to subcool the refrigerant. In someembodiments, the drip system may allow the condensate to contact one ormore heat transfer fins 206 adjacent the subcooling coil 203 and/or thecondensing coil 205.

In an embodiment, the fluid distributor 111 may comprise a spray system.In this embodiment, the fluid distributor may comprise a tubing havingone or more nozzles or spray devices to allow the condensate to flowfrom an interior of the tubing through the nozzles or spray devices toan exterior of the tubing and into contact with the outdoor heatexchanger. The use of nozzles or the like may benefit from the use ofthe optional pump 107 described above in order to provide the pressureassociated with passing the fluid through the nozzles. The spray systemmay be configured to contact the outdoor heat exchanger 114 regardlessof orientation. For example, the spray system may be located above,below, and/or on the side of the outdoor heat exchanger 114. Further,the fluid distributor may be configured to allow at least a portion ofthe condensate to contact the outdoor heat exchanger 114 in a liquidstate. The condensate may then be allowed to evaporate from the outdoorheat exchanger 114, thereby absorbing and removing heat from therefrigerant passing through the outdoor heat exchanger 114.

When the fluid distributor 111 comprises a spray system, the fluiddistributor 111 may be configured to allow the condensate to contact thesubcooling section 202 prior to any condensate contacting the condensingsection 204. In an embodiment, the subcooling section 202 including thesubcooling coil 203 may be located adjacent the fluid distributor 111 orat least the portion thereof comprising the nozzles or spray devices.Since the spray system may be configured to eject the fluid onto thesurfaces within the outdoor heat exchanger 114, the subcooling section202 may be located above, below, or adjacent the condensing section 204.For example, the subcooling coil may be located above, below, orhorizontally aligned with the condensing coil 205. In an embodiment, thedisposition of the subcooling section 202 above the condensing section204 may allow any excess condensate not evaporated in the condensingsection 202 to flow to the condensing section 204. In an embodiment, thespray system may be configured to spray the condensate directly on thesubcooling coil, the condensing coil, and/or one or more heat transferfins 206.

In an embodiment, the fluid distributor 111 may be configured to passthe condensate over at least a portion of the outdoor heat exchanger 114as a vapor. When water evaporates, it can cause the air temperaturesurrounding the water to drop to at or near the wet bulb temperature.The cooling effect can then be used to contact the outdoor heatexchanger 114. In this embodiment, the fluid distributor 111 maycomprise a spray system or a drip system. For a spray system, thecondensate may be sprayed or atomized into a stream of income air, forexample outdoor air forced by the outdoor fan 118. At least a portion ofthe condensate in the air stream can then evaporate and cause thetemperature of the stream of air to be reduced. The air stream can thenpass over at least a portion of the outdoor heat exchanger 114. In anembodiment, the fluid distributor 111 can comprise a drip system wherethe condensate is passed through a porous mesh or other high surfacearea structure. The air stream can then be drawn through the mesh andthe condensate can evaporate, thereby cooling the air stream. The airstream can then pass over at least a portion of the outdoor heatexchanger 114. In some embodiments, the fluid distributor may beconfigured to pass a portion of the condensate over the outdoor heatexchanger 114 as a liquid and another portion as a vapor. In anembodiment, an outdoor air stream cooled using the condensate can beconfigured to pass over the subcooling section 202 prior to passing overthe condensing section 204.

The use of the fluid distributor 111 to pass the condensate over theoutdoor heat exchanger 114 may result in the refrigerant within theoutdoor heat exchanger 114 being cooled, condensed, and/or subcooled. Inan embodiment, the refrigerant can be completely condensed within thecondensing coil 205 and/or the subcooling coil 203. In this embodiment,the refrigerant may leave the outdoor heat exchanger 114 as a liquid.The use of the condensate on the outdoor heat exchanger 114 may increasethe capacity of the outdoor heat exchanger 114. In an embodiment, theuse of the condensate with the fluid distributor 111 may increase thecapacity of the outdoor heat exchanger to cool and condense therefrigerant between about 5% and 50%, between about 10% and 40%, oralternatively between about 15% and 30% relative to the same outdoorheat exchanger 114 not having any condensate distributed over at least aportion thereof. The improvement in the capacity of the outdoor heatexchanger may occur when the condensate is distributed or contacted withany portion of the outdoor heat exchanger 114 including the condensingsection 204 and/or the subcooling section 202.

In some embodiments, the refrigerant can be subcooled within thesubcooling coil 203. In this embodiment, the refrigerant may leave theoutdoor heat exchanger 114 as a subcooled liquid. The amount ofsubcooling may depend on the amount of condensate supplied through thefluid distributor 111, the outdoor air temperature, the contact area ofthe outdoor heat exchanger 114, the incoming temperature and pressure ofthe refrigerant within the outdoor heat exchanger 114, and various otherfactors. In an embodiment, the use of the condensate to subcool therefrigerant within the outdoor heat exchanger may result in therefrigerant passing out of the outdoor heat exchanger 114 having beensubcooled between about 5° F. and about 30° F., about 7° F. and about25° F., or about 10° F. and about 20° F.

Returning to FIG. 1, the system controller 106 may display informationrelated to the operation of the HVAC system 100 and may receive userinputs related to operation of the HVAC system 100. However, the systemcontroller 106 may further be operable to display information andreceive user inputs tangentially and/or unrelated to operation of theHVAC system 100. The system controller 106 may generally comprise atouchscreen interface for displaying information and for receiving userinputs. In some embodiments, the system controller 106 may not comprisea display and may derive all information from inputs from remote sensorsand remote configuration tools. In some embodiments, the systemcontroller 106 may comprise and/or be coupled to a temperature sensorand may further be configured to control heating and/or cooling of zonesassociated with the HVAC system 100. In some embodiments, the systemcontroller 106 may be configured as a thermostat for controlling supplyof conditioned air to one or more zones associated with the HVAC system100.

In some embodiments, the system controller 106 may also selectivelycommunicate with an indoor controller 124 of the indoor unit 102, withan outdoor controller 126 of the outdoor unit 104, and/or with othercomponents of the HVAC system 100. In some embodiments, the systemcontroller 106 may be configured for selective bidirectionalcommunication over a communication bus 128. In some embodiments,portions of the communication bus 128 may comprise a three-wireconnection suitable for communicating messages between the systemcontroller 106 and one or more of the HVAC system 100 componentsconfigured for interfacing with the communication bus 128. Stillfurther, the system controller 106 may be configured to selectivelycommunicate with HVAC system 100 components and/or any other device 130via a communication network 132. In some embodiments, the communicationnetwork 132 may comprise a telephone network, and the other device 130may comprise a telephone. In some embodiments, the communication network132 may comprise the Internet, and the other device 130 may comprise asmartphone and/or other Internet-enabled mobile telecommunicationdevice. In other embodiments, the communication network 132 may alsocomprise a remote server.

The indoor controller 124 may be carried by the indoor unit 102 and maybe configured to receive information inputs, transmit informationoutputs, and otherwise communicate with the system controller 106, theoutdoor controller 126, and/or any other device 130 via thecommunication bus 128 and/or any other suitable medium of communication.In some embodiments, the indoor controller 124 may be configured toreceive information related to a speed of the indoor fan 110, transmit acontrol output to an electric heat relay, transmit information regardingan indoor fan 110 volumetric flow-rate, communicate with and/orotherwise affect control over an air cleaner, and communicate with anindoor expansion device controller. In some embodiments, the indoorcontroller 124 may be configured to communicate with an indoor fancontroller and/or otherwise affect control over operation of the indoorfan 110.

The outdoor controller 126 may be carried by the outdoor unit 104 andmay be configured to receive information inputs, transmit informationoutputs, and otherwise communicate with the system controller 106, theindoor controller 124, and/or any other device via the communication bus128 and/or any other suitable medium of communication. In someembodiments, the outdoor controller 126 may be configured to receiveinformation related to an ambient temperature associated with theoutdoor unit 104, information related to a temperature of the outdoorheat exchanger 114, and/or information related to refrigeranttemperatures and/or pressures of refrigerant entering, exiting, and/orwithin the outdoor heat exchanger 114 and/or the compressor 116. In someembodiments, the outdoor controller 126 may be configured to transmitinformation related to monitoring, communicating with, and/or otherwiseaffecting control over the outdoor fan 118, a compressor sump heater, asolenoid of the reversing valve, a relay associated with adjustingand/or monitoring a refrigerant charge of the HVAC system 100, aposition of the indoor metering device 112, and/or a position of theoutdoor metering device 120. The outdoor controller 126 may further beconfigured to communicate with a compressor drive controller that isconfigured to electrically power and/or control the compressor 116.

In operation, the HVAC system 100 may be used in a cooling mode in whichheat is absorbed by refrigerant at the indoor heat exchanger 108 andheat is rejected from the refrigerant at the outdoor heat exchanger 114.In the cooling mode, a cooled and pressurized refrigerant may bereceived at the expansion device 112 through line 117. The refrigerantreceived at the expansion device 112 from the outdoor heat exchanger 114may comprise a refrigerant that is primarily or completely in the liquidrefrigerant. In some embodiments, the refrigerant may comprise asubcooled liquid refrigerant. The expansion device 112 may reduce thepressure of the refrigerant as measured from upstream of the expansiondevice 112 (e.g., in line 117) to downstream of the expansion device 112(e.g., in line 121). The pressure differential across the expansiondevice 112 may allow the refrigerant downstream of the expansion device112 to expand and/or at least partially convert to a two-phase(gas/liquid) mixture.

The two phase refrigerant may enter the indoor heat exchanger 108through line 121. As the refrigerant is passed through the indoor heatexchanger 108, the indoor fan 110 may be operated to move air intocontact with the indoor heat exchanger 108, thereby transferring heat tothe refrigerant from the air surrounding the indoor heat exchanger 108.The liquid portion of the two phase mixture may evaporate and thetemperature of the refrigerant may rise in the indoor heat exchanger108.

On the exterior of the indoor heat exchanger 108, the cooler temperatureof the refrigerant may cause any humidity in the air contacting theindoor heat exchanger 108 to condense. The condensate may collect withinthe fluid collection assembly 109. The resulting condensate may passthrough a port 105 in the fluid collection assembly 109 and pass througha condensate line 113 to the fluid distributor 111. The condensate maybe pumped by the optional pump 107 to aid in transferring the condensatefrom the fluid collection assembly 109 to the fluid distributor 111.

The refrigerant may pass out of the indoor heat exchanger 108 throughline 119 and enter the compressor 116. The compressor 116 may operate tocompress the refrigerant and pump the resulting relatively hightemperature and high pressure compressed refrigerant from the compressor116 to the outdoor heat exchanger 114 through line 115. As therefrigerant is passed through the outdoor heat exchanger 114, theoutdoor fan 118 may be operated to move a fluid (e.g., outdoor air) intocontact with the outdoor heat exchanger 114, thereby transferring heatfrom the refrigerant to the air surrounding the outdoor heat exchanger114. The refrigerant entering the outdoor heat exchanger 114 mayprimarily comprise a vapor and the refrigerant passing out of theoutdoor heat exchanger 114 may primarily comprise liquid phaserefrigerant. The refrigerant may flow from the outdoor heat exchanger114 to the expansion device 112 to repeat the process.

In some embodiments, the outdoor heat exchanger 114 may comprise acondensing section and a subcooling section. The refrigerant enteringthe outdoor heat exchanger 114 through line 115 may first enter thecondensing section 204. As heat is transferred from the refrigerant tothe air passing over the outdoor heat exchanger, 114, the refrigerantmay at least partially condense within the condensing section 204. Theat least partially condensed refrigerant may then enter the subcoolingsection 202 where the refrigerant may be completely condensed, and insome embodiments, subcooled below the condensation temperature. Theoutdoor fan 118 may be configured to allow the air entering the outdoorheat exchanger 114 to contact the subcooling section 202 before orconcurrently with the condensing section 204.

In addition to the outdoor fan 118 operating, the fluid distributor 111may also distribute the condensate over at least a portion of theoutdoor heat exchanger 114 as the refrigerant passes through the outdoorheat exchanger 114. The fluid distributor 111 may be configured to passthe condensate over the outdoor heat exchanger 114 in a liquid and/orvapor form. In some embodiments, the fluid distributor 111 may beconfigured to distribute the condensate over a subcooling portion 202(e.g., a subcooling coil) of the outdoor heat exchanger 114 prior topassing the condensate over at least a portion of the condensing section204 (e.g., a condensing coil). The condensate may evaporate, and theresulting evaporation may absorb heat from the refrigerant in theoutdoor heat exchanger 114. For example, the condensate may beevaporated when the condensate is in contact with the outdoor heatexchanger 114 (e.g., the condensing coil, the subcooling coil, etc.).The heat transfer may result in the condensation and/or subcooling ofthe refrigerant in the outdoor heat exchanger 114. In some embodiments,the refrigerant may be subcooled in an amount in the range of about 5°F. to about 30° F.

While the HVAC system described above refers to a system that canutilize the condensate at or near the time that it is generated, the useof the system to store and supply the condensate to the outdoor heatexchanger 114 at a later time is shown in the embodiment depicted inFIG. 3. The simplified diagram of the HVAC system 300 is similar in manyrespect to the HVAC described with respect to FIGS. 1 and 2, andaccordingly, similar components will not be described for the sake orbrevity. In an embodiment, any of the components and embodimentsdescribed with respect to the indoor unit 102, the outdoor unit, 104,the controller 106, and/or the outdoor heat exchanger 114 herein may beused with the HVAC system 300.

The main difference between the HVAC system 300 and the HVAC system 100is the presence of a condensate storage vessel 302. The condensatestorage vessel 302 may serve to receive and collect the condensate fromthe indoor heat exchanger 108 and hold it in reserve for use with theoutdoor heat exchanger 114. As noted above, the condensate may begenerated at the indoor heat exchanger 108 during the operation of theHVAC unit 300, which may occur at peak demand conditions as well asduring off-peak demand times. In order to utilize the added efficiencyof the evaporative cooling during certain periods such as peak demandperiods (e.g., during the hottest parts of the hottest days of the yearand/or the electric utility requests or incentivizes energyconservation), the condensate storage vessel 302 may store thecondensate until a threshold system condition (e.g., a temperature,load, cooling rate, electricity cost, etc.) is met or exceeded. In thisway the efficiency of the HVAC system 300 may be improved at a desiredtime such as during a peak demand period.

The condensate storage vessel 302 may be fluidly coupled to the fluidcollection assembly 109 through condensate line 313. In someembodiments, an optional pump 307 may be disposed between and in fluidcommunication with the port 105 and the condensate storage vessel 302.The pump 307 may generally be configured to provide the driving force tocause the condensate to flow from the fluid collection assembly 109 tothe condensate storage vessel 302. Any suitably sized pump 307 may beused to transfer the condensate from the fluid collection assembly 109to the condensate storage vessel 302. Various factors may be consideredwhen selecting the type and capacity (e.g., the volumetric capacity,pumping head, etc.) of the pump 307 such as the relative locations ofthe fluid collection assembly 109, the fluid losses associated with thefluid conduits between the pump 307 and the condensate storage vessel302, the fluid head within the condensate storage vessel 302, the amountof condensate generated on the indoor heat exchanger 108, and the like.In an embodiment, the pump may comprise a positive displacement pump, acentrifugal pump, or any other suitable pump, and the pump 307 mayoperate continuously, intermittently, and/or selectively, for example,when a condensate level is detected in the fluid collection assembly 109(using, for example, a fluid level detector).

The condensate storage vessel 302 may comprise any vessel capable ofretaining the condensate from the fluid collection assembly 109. In anembodiment, the condensate storage vessel 302 may comprise a tank havingany suitable shape (e.g., cylindrical, rectilinear, etc.). Thecondensate storage vessel 302 may be configured to hold at least about0.01 gallons, at least about 0.05 gallons, at least about 0.1 gallons,at least about 0.2 gallons, at least about 0.3 gallons, at least about0.4 gallons, at least about 0.5 gallons, at least about 0.7 gallons, atleast about 1.0 gallons, at least about 2.0 gallons, at least about 3.0gallons, at least about 4 gallons, or at least about 5.0 gallons. Thecondensate storage vessel 302 may be configured to hold up to about 100gallons, up to about 75 gallons, up to about 50 gallons, up to about 25gallons, up to about 20 gallons, up to about 15 gallons, up to about 14gallons, up to about 13 gallons, up to about 12 gallons, up to about 11gallons, up to about 10 gallons, up to about 9 gallons, up to about 8gallons, or up to about 7 gallons. While illustrated as a singlecontainer, any number of condensate storage vessels may be arranged inseries and/or parallel to allow for the storage of a desired amount ofcondensate. For example, a plurality of condensate storage vessels maybe used in the HVAC system 300 and fluidly coupled to the fluidcollection assembly 109 and the fluid distributor 111.

The condensate storage vessel 302 may be fluidly coupled to the fluiddistributor 111, and the condensate storage vessel 302 can be located atany point between the fluid collection assembly 109 and the fluiddistributor 111. In an embodiment, the condensate storage vessel 302 maybe located within the indoor unit 102. In some embodiments, thecondensate storage vessel 302 can be located within the outdoor unit104, for example, at or near the outdoor heat exchanger 114. In stillother embodiments, the condensate storage vessel 302 may be locatedoutside of the indoor unit 102 and the outdoor unit 104.

The condensate storage vessel 302 may be fluidly coupled to the fluiddistributor 111 through condensate line 304. In some embodiments, anoptional pump 308 may be disposed downstream of and in fluidcommunication with the condensate storage vessel 302. The pump 308 maybe fluidly coupled to the fluid distributor 111. The pump 308 maygenerally be configured to provide the driving force to cause thecondensate to flow from the condensate storage vessel 302 to the fluiddistributor 111. Any suitably sized pump 308 may be used to transfer thecondensate from the condensate storage vessel 302 to the fluiddistributor 111. Various factors may be considered when selecting thetype and capacity (e.g., the volumetric capacity, pumping head, etc.) ofthe pump 308 such as the relative locations of the condensate storagevessel 302, the fluid losses associated with the fluid conduits betweenthe pump 308 and the fluid distributor, the fluid pressure lossassociated with the fluid distributor 111, the amount of condensatestored within the condensate storage vessel 302, the flowrate of thecondensate to the fluid distributor 111, and the like. In an embodiment,the pump may comprise a positive displacement pump, a centrifugal pump,or any other suitable pump, and the pump 308 may operate continuously,intermittently, and/or selectively, for example, when the controlleractuates the pump 308, as described in more detail below. In anembodiment, only one of the optional pumps 307, 308 may be present inthe system. For example, the pump 307 may not be present and thecondensate may flow by gravity flow to the condensate storage vessel302. The pump 308 may then be used to transfer the condensate to thefluid distributor 111.

In operation, the HVAC system 300 may operate as described with respectto the HVAC system 100 in FIG. 1. In an embodiment, the HVAC system 100may be used in a cooling mode in which heat is absorbed by refrigerantat the indoor heat exchanger 108 and heat is rejected from therefrigerant at the outdoor heat exchanger 114. In the cooling mode, theexterior of the indoor heat exchanger 108 may be cooler than the airpassing over it, and the cooler temperature of the refrigerant may causeany humidity in the air contacting the indoor heat exchanger 108 tocondense. The condensate may collect within the fluid collectionassembly 109, and pass through a port 105 in the fluid collectionassembly 109 to the condensate storage vessel 302 through condensateline 313. The condensate may be pumped by the optional pump 307 to aidin transferring the condensate from the fluid collection assembly 109 tothe condensate collection vessel 302.

During use, the condensate may collect within the condensate storagevessel 302. In an embodiment, the condensate may collect within thecondensate storage vessel 302 during one or more operational periods,for example, over multiple operations of the HVAC system 300 in thecooling mode. In an embodiment, the condensate may collect duringnon-peak hours of the day. In some embodiments, the condensate maycollect over a period of days, weeks, or even months without being usedwith the outdoor heat exchanger 114.

The condensate may be used based on various considerations. In anembodiment, the controller 106 may be configured to use the condensateunder one or more conditions, for example, in response to one or moreconditions or thresholds being achieved and/or at one or more specifiedtime periods. In an embodiment, the condensate may be utilized based onan input associated with the HVAC system 300. The controller 106 maydetect a condition associated with the system 300 and initiate the pump307 and/or the pump 308 to provide the condensate to the fluiddistributor 111. In an embodiment, the condition associated with use ofthe condensate may include a time period such as a peak demand timeperiod. For example, the time period may include a time of the day, aday of the week, a month of the year, a season, or any combinationthereof. As a further example, the condensate may be used during thehottest two hours of the day (e.g., 3:00-5:00 PM) in summer season(e.g., July to August) at a given location.

In some embodiments, the condition may be a measured condition. Thesystem 300 may comprise one or more sensors for detecting systemconditions including, but not limited to, the interior air temperature(e.g., room air temperature measured by a thermostat), the exterior airtemperature (e.g., the outside air temperature), the HVAC system runningtime, the refrigerant temperature at the outlet of the outdoor heatexchanger 114, the refrigerant temperature at the inlet of the outdoorheat exchanger 114, the vapor quality of the refrigerant at the outletof the outdoor heat exchanger 114, a compressor power load, or any othercondition associated with the system. The controller 106 may initiateuse of the condensate when one or more of the measured conditionsexceeds a threshold, which may include detecting a value above or belowa predetermined value. For example, the controller 106 may initiate theuse of the condensate when the refrigerant outlet temperature and/orquality rises above a predetermined value at the outlet of the outdoorheat exchanger. The controller 106 may also calculate one or more valuesbased on the measured conditions to determine if one or more thresholdsare exceeded. In an embodiment, the controller 106 may calculate atemperature difference between an interior and exterior temperature, arefrigerant temperature difference around the outdoor heat exchanger 114(e.g., a temperature difference between a refrigerant temperature at theinlet and outlet of the outdoor heat exchanger), a cooling rate based onone or more of the temperatures and the time the system has beenrunning, or the like. The controller 106 may then initiate the use ofthe condensate based on the calculated value meeting or exceeding athreshold value.

In some embodiments, the controller 106 may initiate the use of thecondensate based on an external signal. In an embodiment, the controller106 may receive a signal from the communication network 132 thattriggers the use of the condensate. For example, a utility supplier maybe in communication with the controller 106 over the communicationnetwork 132, and the controller 106 may receive a signal from theutility supplier to initiate the use of the condensate. Such a signalmay be useful during high demand periods to allow the HVAC system 300 tocool more efficiently and reduce the overall electricity usage.Similarly, a monitoring service provided by the manufacturer or a thirdparty may similarly generate a signal to allow the controller toinitiate the use of the condensate. When a signal is used to initiatethe use of the condensate, the signal may contain a time period duringwhich to use the condensate, the controller may automatically utilizethe condensate for a predetermined period, and/or a second signal may begenerated to cause the cessation of the use of the condensate.

Upon initiating the use of the condensate, the controller 106 mayactuate the pump 307 and/or the pump 308. In some embodiments, one ormore valves may be opened upon receiving an actuation signal. Onceinitiated, the condensate may pass from the condensate storage vessel302 to the fluid distributor 111. The fluid distributor 111 maydistribute the condensate over at least a portion of the outdoor heatexchanger 114 as the refrigerant passes through the outdoor heatexchanger 114. The fluid distributor 111 may be configured using any ofthe embodiments described herein, and may operate as described withrespect to FIG. 1. Upon using all of the available condensate and/orceasing the flow of the condensate from the condensate storage vessel302, the system may cease operation of the cooling mode or continue tooperate without the use of the condensate distribution over the outdoorheat exchanger 114.

While the HVAC system described above refers to a system that cangenerally be used in a cooling mode, the use of the system to supply thecondensate to the outdoor heat exchanger 114 can also be used in areversible HVAC system 400 as shown in the embodiment depicted in FIG.4. The simplified diagram of the HVAC system 400 is similar in manyrespect to the HVAC described with respect to FIGS. 1 and 2, andaccordingly, similar components will not be described for the sake orbrevity. In an embodiment, the HVAC system 400 may comprise a so-calledheat pump system that may be selectively operated to implement one ormore substantially closed thermodynamic refrigeration cycles to providea cooling functionality and/or a heating functionality. The HVAC system400 may generally comprise an indoor unit 402, an outdoor unit 404, anda controller 106. The system controller 106 may generally comprise thosecomponent described above with respect to the controllers.

The indoor unit 402 generally comprises an indoor heat exchanger 108, afluid collection assembly 109, an indoor fan 110, an indoor meteringdevice 412, and an optional pump 107. The indoor heat exchanger 108, thefluid collection assembly 109, the indoor fan 110, and the optional pump107 may be the same or similar to the elements described herein. Theindoor metering device 412 may be similar to the expansion device 112described herein. For example, the indoor metering device 412 maycomprise an electronically controlled motor driven electronic expansionvalve (EEV). In some embodiments, the indoor metering device 412 maycomprise a thermostatic expansion valve, a capillary tube assembly,and/or any other suitable metering device. The indoor metering device412 may comprise and/or be associated with a refrigerant check valveand/or refrigerant bypass for use when a direction of refrigerant flowthrough the indoor metering device 412 is such that the indoor meteringdevice 412 is not intended to meter or otherwise substantially restrictflow of the refrigerant through the indoor metering device 412.

The outdoor unit 404 generally comprises an outdoor heat exchanger 114,a compressor 116, an outdoor fan 118, a fluid distributor 111, anoutdoor metering device 420, and a reversing valve 422. The outdoor heatexchanger 114, the compressor 116, the outdoor fan 118, and the fluiddistributor may be the same as or similar to any of the correspondingcomponents described herein. The outdoor metering device 420 maycomprise a thermostatic expansion valve. In some embodiments, theoutdoor metering device 420 may comprise an electronically controlledmotor driven EEV similar to indoor metering device 412, a capillary tubeassembly, and/or any other suitable metering device. The outdoormetering device 420 may comprise and/or be associated with a refrigerantcheck valve and/or refrigerant bypass for use when a direction ofrefrigerant flow through the outdoor metering device 420 is such thatthe outdoor metering device 420 is not intended to meter or otherwisesubstantially restrict flow of the refrigerant through the outdoormetering device 420.

The reversing valve 422 may be configured to selectively control oralter a flow path of refrigerant in the HVAC system 400 as described ingreater detail below. In an embodiment, the reversing valve 422 maycomprise so-called four-way reversing valve. The reversing valve 422 maycomprise an electrical solenoid or other device configured toselectively move a component of the reversing valve 422 betweenoperational positions.

As schematically illustrated in FIG. 4, the HVAC system 400 is shownconfigured for operating in a so-called cooling mode in which heat isabsorbed by refrigerant at the indoor heat exchanger 108 and heat isrejected from the refrigerant at the outdoor heat exchanger 114. In someembodiments, the compressor 116 may be operated to compress refrigerantand pump the relatively high temperature and high pressure compressedrefrigerant from the compressor 116 to the outdoor heat exchanger 114through the reversing valve 122 and to the outdoor heat exchanger 114.As the refrigerant is passed through the outdoor heat exchanger 114, theoutdoor fan 118 may be operated to move air into contact with theoutdoor heat exchanger 114, thereby transferring heat from therefrigerant to the air surrounding the outdoor heat exchanger 114. Thefluid distributor 111 can be configured to pass the condensate over atleast a portion of the outdoor heat exchanger (e.g., the subcoolingsection) in order to cool and/or subcool the refrigerant, as describedabove. The refrigerant leaving the outdoor heat exchanger 114 mayprimarily comprise liquid phase refrigerant, which in some embodimentsmay be subcooled. The refrigerant may flow from the outdoor heatexchanger 114 to the indoor metering device 412 through and/or aroundthe outdoor metering device 420 which does not substantially impede flowof the refrigerant in the cooling mode. The indoor metering device 412may meter passage of the refrigerant through the indoor metering device412 so that the refrigerant downstream of the indoor metering device 412is at a lower pressure than the refrigerant upstream of the indoormetering device 412. The pressure differential across the indoormetering device 412 may allow the refrigerant downstream of the indoormetering device 412 to expand and/or at least partially convert to atwo-phase (vapor and gas) mixture.

The two phase refrigerant may enter the indoor heat exchanger 108. Asthe refrigerant is passed through the indoor heat exchanger 108, theindoor fan 110 may be operated to move air into contact with the indoorheat exchanger 108, thereby transferring heat to the refrigerant fromthe air surrounding the indoor heat exchanger 108, and causingevaporation of the liquid portion of the two phase mixture. The coolerrefrigerant may cause moisture in the air moving in contact with theindoor heat exchanger 108 to condense. The condensate may collect in thefluid collection assembly 109 and be transferred to the fluiddistributor 111 in order to cool the refrigerant in the outdoor heatexchanger 114. The optional pump or driving device may be used totransfer the condensate from the fluid collection assembly to the fluiddistributor. The refrigerant leaving the indoor heat exchanger 108 maythereafter re-enter the compressor 116 after passing through thereversing valve 422.

The HVAC system 100 may also be operated in the so-called heating mode.In this configuration, the reversing valve 422 may be controlled toalter the flow path of the refrigerant, the indoor metering device 412may be disabled and/or bypassed, and the outdoor metering device 420 maybe enabled. In the heating mode, refrigerant may flow from thecompressor 116 to the indoor heat exchanger 108 through the reversingvalve 422, the refrigerant may be substantially unaffected by the indoormetering device 412, the refrigerant may experience a pressuredifferential across the outdoor metering device 420, the refrigerant maypass through the outdoor heat exchanger 114, and the refrigerant mayreenter the compressor 116 after passing through the reversing valve422. Most generally, operation of the HVAC system 100 in the heatingmode reverses the roles of the indoor heat exchanger 108 and the outdoorheat exchanger 114 as compared to their operation in the cooling mode.In the heating mode, heat may be released from the refrigerant in theindoor heat exchanger 108. As a result, condensate may not form, andfluid may be transferred from the fluid collection assembly 109 to thefluid distributor 111. As a result, the use of the condensate may beused in the cooling mode and not in the heating mode.

In some embodiments, various portions of the system such as thecontroller 106 may comprise or operate using a computer. For example,the use of the controller 106 to determine one or more conditionsassociated with the system and trigger the release of the condensate mayoccur based on instructions stored in a memory and executed on aprocessor associated with the controller. FIG. 5 illustrates a computersystem 580 suitable for implementing one or more embodiments disclosedherein. The computer system 580 includes a processor 582 (which may bereferred to as a central processor unit or CPU) that is in communicationwith memory devices including secondary storage 584, read only memory(ROM) 586, random access memory (RAM) 588, input/output (I/O) devices590, and network connectivity devices 592. The processor 582 may beimplemented as one or more CPU chips.

It is understood that by programming and/or loading executableinstructions onto the computer system 580, at least one of the CPU 582,the RAM 588, and the ROM 586 are changed, transforming the computersystem 580 in part into a particular machine or apparatus having thenovel functionality taught by the present disclosure. It is fundamentalto the electrical engineering and software engineering arts thatfunctionality that can be implemented by loading executable softwareinto a computer can be converted to a hardware implementation by wellknown design rules. Decisions between implementing a concept in softwareversus hardware typically hinge on considerations of stability of thedesign and numbers of units to be produced rather than any issuesinvolved in translating from the software domain to the hardware domain.Generally, a design that is still subject to frequent change may bepreferred to be implemented in software, because re-spinning a hardwareimplementation is more expensive than re-spinning a software design.Generally, a design that is stable that will be produced in large volumemay be preferred to be implemented in hardware, for example in anapplication specific integrated circuit (ASIC), because for largeproduction runs the hardware implementation may be less expensive thanthe software implementation. Often a design may be developed and testedin a software form and later transformed, by well known design rules, toan equivalent hardware implementation in an application specificintegrated circuit that hardwires the instructions of the software. Inthe same manner as a machine controlled by a new ASIC is a particularmachine or apparatus, likewise a computer that has been programmedand/or loaded with executable instructions may be viewed as a particularmachine or apparatus.

The secondary storage 584 is typically comprised of one or more diskdrives or tape drives and is used for non-volatile storage of data andas an over-flow data storage device if RAM 588 is not large enough tohold all working data. Secondary storage 584 may be used to storeprograms which are loaded into RAM 588 when such programs are selectedfor execution. The ROM 586 is used to store instructions and perhapsdata which are read during program execution. ROM 586 is a non-volatilememory device which typically has a small memory capacity relative tothe larger memory capacity of secondary storage 584. The RAM 588 is usedto store volatile data and perhaps to store instructions. Access to bothROM 586 and RAM 588 is typically faster than to secondary storage 584.The secondary storage 584, the RAM 588, and/or the ROM 586 may bereferred to in some contexts as computer readable storage media and/ornon-transitory computer readable media.

I/O devices 590 may include printers, video monitors, liquid crystaldisplays (LCDs), touch screen displays, keyboards, keypads, switches,dials, mice, track balls, voice recognizers, card readers, paper tapereaders, or other well-known input devices.

The network connectivity devices 592 may take the form of modems, modembanks, Ethernet cards, universal serial bus (USB) interface cards,serial interfaces, token ring cards, fiber distributed data interface(FDDI) cards, wireless local area network (WLAN) cards, radiotransceiver cards such as code division multiple access (CDMA), globalsystem for mobile communications (GSM), long-term evolution (LTE),worldwide interoperability for microwave access (WiMAX), and/or otherair interface protocol radio transceiver cards, and other well- knownnetwork devices. These network connectivity devices 592 may enable theprocessor 582 to communicate with the Internet or one or more intranets.With such a network connection, it is contemplated that the processor582 might receive information from the network, or might outputinformation to the network in the course of performing theabove-described method steps. Such information, which is oftenrepresented as a sequence of instructions to be executed using processor582, may be received from and outputted to the network, for example, inthe form of a computer data signal embodied in a carrier wave.

Such information, which may include data or instructions to be executedusing processor 582 for example, may be received from and outputted tothe network, for example, in the form of a computer data baseband signalor signal embodied in a carrier wave. The baseband signal or signalembedded in the carrier wave, or other types of signals currently usedor hereafter developed, may be generated according to several methodswell known to one skilled in the art. The baseband signal and/or signalembedded in the carrier wave may be referred to in some contexts as atransitory signal.

The processor 582 executes instructions, codes, computer programs,scripts which it accesses from hard disk, floppy disk, optical disk(these various disk based systems may all be considered secondarystorage 584), ROM 586, RAM 588, or the network connectivity devices 592.While only one processor 582 is shown, multiple processors may bepresent. Thus, while instructions may be discussed as executed by aprocessor, the instructions may be executed simultaneously, serially, orotherwise executed by one or multiple processors. Instructions, codes,computer programs, scripts, and/or data that may be accessed from thesecondary storage 584, for example, hard drives, floppy disks, opticaldisks, and/or other device, the ROM 586, and/or the RAM 588 may bereferred to in some contexts as non-transitory instructions and/ornon-transitory information.

In an embodiment, the computer system 580 may comprise two or morecomputers in communication with each other that collaborate to perform atask. For example, but not by way of limitation, an application may bepartitioned in such a way as to permit concurrent and/or parallelprocessing of the instructions of the application. Alternatively, thedata processed by the application may be partitioned in such a way as topermit concurrent and/or parallel processing of different portions of adata set by the two or more computers. In an embodiment, virtualizationsoftware may be employed by the computer system 580 to provide thefunctionality of a number of servers that is not directly bound to thenumber of computers in the computer system 580. For example,virtualization software may provide twenty virtual servers on fourphysical computers. In an embodiment, the functionality disclosed abovemay be provided by executing the application and/or applications in acloud computing environment. Cloud computing may comprise providingcomputing services via a network connection using dynamically scalablecomputing resources. Cloud computing may be supported, at least in part,by virtualization software. A cloud computing environment may beestablished by an enterprise and/or may be hired on an as-needed basisfrom a third party provider. Some cloud computing environments maycomprise cloud computing resources owned and operated by the enterpriseas well as cloud computing resources hired and/or leased from a thirdparty provider.

In an embodiment, some or all of the functionality disclosed above maybe provided as a computer program product. The computer program productmay comprise one or more computer readable storage medium havingcomputer usable program code embodied therein to implement thefunctionality disclosed above. The computer program product may comprisedata structures, executable instructions, and other computer usableprogram code. The computer program product may be embodied in removablecomputer storage media and/or non-removable computer storage media. Theremovable computer readable storage medium may comprise, withoutlimitation, a paper tape, a magnetic tape, magnetic disk, an opticaldisk, a solid state memory chip, for example analog magnetic tape,compact disk read only memory (CD-ROM) disks, floppy disks, jump drives,digital cards, multimedia cards, and others. The computer programproduct may be suitable for loading, by the computer system 580, atleast portions of the contents of the computer program product to thesecondary storage 584, to the ROM 586, to the RAM 588, and/or to othernon-volatile memory and volatile memory of the computer system 580. Theprocessor 582 may process the executable instructions and/or datastructures in part by directly accessing the computer program product,for example by reading from a CD-ROM disk inserted into a disk driveperipheral of the computer system 580. Alternatively, the processor 582may process the executable instructions and/or data structures byremotely accessing the computer program product, for example bydownloading the executable instructions and/or data structures from aremote server through the network connectivity devices 592. The computerprogram product may comprise instructions that promote the loadingand/or copying of data, data structures, files, and/or executableinstructions to the secondary storage 584, to the ROM 586, to the RAM588, and/or to other non-volatile memory and volatile memory of thecomputer system 580.

In some contexts, the secondary storage 584, the ROM 586, and the RAM588 may be referred to as a non-transitory computer readable medium or acomputer readable storage media. A dynamic RAM embodiment of the RAM588, likewise, may be referred to as a non- transitory computer readablemedium in that while the dynamic RAM receives electrical power and isoperated in accordance with its design, for example during a period oftime during which the computer specification 580 is turned on andoperational, the dynamic RAM stores information that is written to it.Similarly, the processor 582 may comprise an internal RAM, an internalROM, a cache memory, and/or other internal non-transitory storageblocks, sections, or components that may be referred to in some contextsas non-transitory computer readable media or computer readable storagemedia.

At least one embodiment is disclosed and variations, combinations,and/or modifications of the embodiment(s) and/or features of theembodiment(s) made by a person having ordinary skill in the art arewithin the scope of the disclosure. Alternative embodiments that resultfrom combining, integrating, and/or omitting features of theembodiment(s) are also within the scope of the disclosure. Wherenumerical ranges or limitations are expressly stated, such expressranges or limitations should be understood to include iterative rangesor limitations of like magnitude falling within the expressly statedranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4,etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example,whenever a numerical range with a lower limit, R₁, and an upper limit,R_(u), is disclosed, any number falling within the range is specificallydisclosed. In particular, the following numbers within the range arespecifically disclosed: R=R₁+k*(R_(u)-R₁), wherein k is a variableranging from 1 percent to 100 percent with a 1 percent increment, i.e.,k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . , 50percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97percent, 98 percent, 99 percent, or 100 percent. Moreover, any numericalrange defined by two R numbers as defined in the above is alsospecifically disclosed. Use of the term “optionally” with respect to anyelement of a claim means that the element is required, or alternatively,the element is not required, both alternatives being within the scope ofthe claim. Use of broader terms such as comprises, includes, and havingshould be understood to provide support for narrower terms such asconsisting of, consisting essentially of, and comprised substantiallyof. Accordingly, the scope of protection is not limited by thedescription set out above but is defined by the claims that follow, thatscope including all equivalents of the subject matter of the claims.Each and every claim is incorporated as further disclosure into thespecification and the claims are embodiment(s) of the present invention.

What is claimed is:
 1. A refrigeration system comprising: an indoorexchanger; an outdoor exchanger comprising: a main coil, and asubcooling coil, wherein the indoor exchanger and the outdoor exchangerare operable in at least a cooling mode, wherein the indoor coil isconfigured to absorb heat in the cooling mode, and wherein the outdoorcoil is configured to release heat in the cooling mode; a fluidcollector configured to collect condensate from the indoor exchanger;and a fluid distributor configured to pass the condensate from the fluidcollector over at least a portion of the outdoor exchanger.
 2. Therefrigeration system of claim 1, further comprising a pump configured toreceive the condensate and pass the condensate to the fluid distributor.3. The refrigeration system of claim 1, wherein the fluid distributor isconfigured to pass the condensate over at least a portion of thesubcooling coil.
 4. The refrigeration system of claim 1, wherein theindoor exchanger and the outdoor exchanger are operable in a heatingmode, wherein the indoor coil is configured to release heat in theheating mode, and wherein the outdoor coil is configured to absorb heatin the heating mode.
 5. The refrigeration system of claim 1, wherein thefluid distributor comprises a drip system or a spray nozzle.
 6. Therefrigeration system of claim 1, wherein the fluid distributor isconfigured to pass the condensate over at least the portion of theoutdoor exchanger in a liquid state.
 7. The refrigeration system ofclaim 1, further comprising: a condensate storage vessel in fluidcommunication with the fluid collector and the fluid distributor.
 8. Acooling system comprising: an evaporator exchanger; a condenserexchanger comprising: a main coil, and a subcooling coil, wherein theevaporator coil is configured to absorb heat to evaporate at least aportion of a refrigerant, wherein the condenser coil is configured torelease heat and condense at least a portion of the refrigerant in themain coil, and wherein the condenser coil is configured to subcool atleast a portion of the refrigerant in the subcooling coil; a fluidcollector configured to collect condensate from the evaporatorexchanger; a fluid conduit in fluid communication with the fluidcollector; and a fluid distributor in fluid communication with the fluidconduit, wherein the fluid distributor is configured to pass thecondensate over at least a portion of the condenser exchanger.
 9. Thecooling system of claim 8, further comprising a pump in fluidcommunication with the fluid conduit, wherein the pump is configured topass the fluid to the fluid distributor.
 10. The cooling system of claim8, wherein the fluid distributor comprises a drip system disposed abovethe condenser exchanger.
 11. The cooling system of claim 10, wherein thefluid distributor is configured to pass the condensate over at least aportion of the subcooling coil.
 12. The cooling system of claim 11,wherein the subcooling coil is disposed above the main coil.
 13. Thecooling system of claim 8, further comprising: a compressor disposed ina first fluid line between an outlet of the evaporator exchanger and aninlet of the condenser exchanger, wherein the compressor is configuredto draw a refrigerant from the outlet of the evaporator exchanger,compress the refrigerant, and pass the refrigerant to inlet of thecondenser exchanger; and an expansion device disposed in a second fluidline between an outlet of the condenser exchanger and an inlet of theevaporator exchanger, wherein the expansion device is configured toreceive a refrigerant from the outlet of the condenser exchanger, expandthe refrigerant, and pass the refrigerant to inlet of the evaporatorexchanger.
 14. The cooling system of claim 8, further comprising ablower, wherein the blower is configured to cause air to pass over thecondenser exchanger when the condensate is passed over at least theportion of the condenser exchanger.
 15. The cooling system of claim 8,further comprising: a condensate storage vessel in fluid communicationwith the fluid collector and the fluid distributor.
 16. The coolingsystem of claim 15, further comprising: a controller, wherein thecontroller is configured to: cause the condensate storage vessel tocollect condensate from the fluid collector; detect a conditionassociated with the cooling system; and transfer the condensate from thecondensate storage vessel to the fluid distributor when the conditionexceeds a threshold.
 17. A method of cooling a refrigerant, the methodcomprising: evaporating a refrigerant in an indoor exchanger; condensingwater on the indoor exchanger during the evaporating; collecting thewater condensed on the indoor exchanger; distributing the water over atleast a portion of an outdoor exchanger; evaporating the water; andcooling the refrigerant in the outdoor exchanger in response to theevaporating.
 18. The method of claim 17, wherein evaporating the watercomprises evaporating the water when the water is in contact with theoutdoor exchanger.
 19. The method of claim 17, wherein distributing thewater over at least the portion of the outdoor exchanger comprisesdistributing the water over a subcooling coil of the outdoor exchanger.20. The method of claim 19, wherein cooling the refrigerant comprisessubcooling the refrigerant in the subcooling coil in response toevaporating the water.
 21. The method of claim 20, wherein therefrigerant is subcooled at least about 5° F. to about 30° F.
 22. Themethod of claim 17, further comprising: pumping the water from theindoor exchanger to the outdoor exchanger.
 23. The method of claim 17,further comprising: completely condensing the refrigerant leaving theoutdoor exchanger in response to cooling the refrigerant.
 24. The methodof claim 17, wherein collecting the water comprises storing the watercondensed on the indoor exchanger in a condensate storage vessel. 25.The method of claim 24, where distributing the water over at least aportion of the outdoor exchanger comprises passing the water from thecondensate storage vessel to the outdoor exchanger.
 26. The method ofclaim 25, wherein passing the water from the condensate storage vesseloccurs in response to a controller determining that the method isoccurring at a peak demand period.
 27. The method of claim 24, furthercomprising: measuring a condition associated with at least one of theindoor exchanger, the outdoor exchanger, an indoor location, or anoutdoor location; comparing the condition with one or more thresholds,and releasing the water from the condensate storage vessel when thecondition exceeds at least one threshold.